const isLogin = true;
function App() {
    return (
        <div className="App">
            this is App
            {/* 逻辑与 && */}
            {isLogin && <span>this is span</span>}
            {/* 三元运算符 */}
            {isLogin ? <span>jack</span> : <span>loading...</span>}
        </div>
    );
}

export default App;
